The background description includes information that may be useful in understanding the present inventive subject matter. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
Molecule-molecule interactions, including protein-protein interactions and DNA-protein interactions occur in a wide range of biological phenomena, and many of them are often used for detecting and/or diagnosing a pathology and/or progress of a disease or symptoms. For example, detection of antigen-antibody interactions has been used to diagnose or determine a progress of infectious diseases or autoimmune diseases. Traditionally, molecule-molecule interactions are detected by labeling at least one of the molecules with a marker (e.g., fluorescence, biotin, organic dyes, enzyme conjugate, etc.). However, such labeling step takes extra cost and time such that it is very difficult to provide a user a detection results in a short time. Further, most of traditional methods require a liquid phase for signal detections, which often result in undesired nonspecific signals and/or bulk size of detection materials.
Some attempted to detect protein-protein interaction by detecting intrinsic fluorescence of a molecule without labeling the molecule. For example, Li et al., discloses a method of detecting antigen-antibody interactions using deep UV laser-based fluorescence lifetime microscopy. Here, a native fluorescence signal from intrinsic tryptophan emission was observed at 266 nm. However, in Li's method, native fluorescence signal is detected in a liquid phase. See Lee at al., Analytical Biochemistry 367 (2007) 104-110.
Some also attempted to detect conformational changes of a protein by attempt detecting intrinsic fluorescence of a molecule without labeling the molecule. For example, Lee at al. discloses microchip-based system for measuring concentrations and dynamic conformational changes in proteins without any use of extrinsic fluorescent labeling. Similar to Li et al., in Lee's method, difference of intrinsic fluorescence signal of tryptophan is detected to determine any conformational changes of a protein. However, this method is also limited to microfluidic system.
Others attempted to detect protein-protein interaction by detecting size differences before and after the interaction. For example, European Patent Application No. 1300684 to Price discloses detecting ligand-receptor binding by using colloidal magnetic particles. In this method, proteins bind to the colloidal magnetic particles, which increase overall size of the magnetic particle. Thus, the amount of analyte present in the solution can be determined by measuring the size of the magnetic particle associated with the analyte. Yet, this method is also limited to interaction and detection in a liquid phase.
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Thus, there is still a need for improved devices, systems and methods for detecting molecules in a solid state using UV lights in a dry condition.